<template>
  <div>计算和: {{count}}</div>
</template>

<script>
  import { EventBus } from './event-bus.js'
  export default {
    data() {
      return {
        count: 0
      }
    },

    mounted() {
      EventBus.$on('addition', param => {
        this.count = this.count + param.num;
      })
    }
  }
</script>
